Decan 1 of Taurus

This is the first ten-degree segment of Taurus, the fixed earth sign, spanning 0 to 10 degrees. Its ruler in the Chaldean order of faces is Mercury, following the continuous assignment of the seven planets to the thirty-six decans around the zodiac. The decans are the most ancient layer of the tradition, beginning as thirty-six Egyptian star groups that rose in succession to divide the year into ten-day weeks and the night into hours, and were absorbed into the Greek zodiac as ten-degree arcs only in the last centuries BCE.

The Golden Dawn, from 1888, mapped the numbered minor cards onto the decans in order; this segment carries the Five of Coins, to which they gave the title Worry, its Mercury-in-Taurus attribution taken directly from the face ruler. That tarot layer is a modern Western construction laid over the older decan scheme, not a feature of the Egyptian or Hellenistic material.

The first decan of Taurus runs from 0 to 10 degrees of the sign and is ruled, in the scheme this atlas records, by Mercury.

The card on the decan

In the Golden Dawn's assignment this decan carries the Five of Coins. The mapping is one to one and exhaustive: the thirty-six small cards numbered two to ten across the four suits match the thirty-six decans exactly, taken in order from the Two of Wands at the first decan of Aries. The suit follows the sign's element, so Taurus is a Earth sign and takes a card of Coins, and the rank follows the position in the sequence, which puts the five here.

Two ruler schemes, and which one this is

Two schemes for decan rulership are in circulation and they disagree. The one recorded here runs the seven planets in Chaldean order continuously round the circle. The other, the triplicity scheme, gives a sign's three decans to the rulers of the three signs of its own element in order, so the rulers stay inside the element and restart at every sign. Both are attested in the tradition, neither is a corruption of the other, and a reader comparing two books will find them differing here without either being wrong.

What the atlas is recording

The degrees and the ruler are the attributions this atlas holds for this decan, and the card is the Golden Dawn's. All of them are traditions with variants rather than settled facts, and the decan itself, as a ten degree segment of a sign, is the only part that is simply arithmetic.